Tackle large yards with the quick-cutting 2X20V MAX* XR® Brushless Cordless 21-1/2 in. Rear Wheel Drive Self-Propelled Mower. The mower features a brushless, direct drive motor that was engineered to lessen your workload and provide long runtime. Rear wheel drive delivers self-propulsion which takes much of the strain off of your arms, back, and legs without sacrificing mowing power. Innovative auto-sensing technology adjusts RPMs while working so you can cut thick grass whether you are mulching, bagging, or side discharging.